The present invention relates to an individual-segment rotor having an axis of rotation and a plurality of laminated core segments which are arranged around the axis of rotation. The present invention further relates to a method for producing an individual-segment rotor by arranging a plurality of laminated core segments around an axis of rotation.
Individual-segment rotors for electric motors with flux concentration are characterized in that the rotor is provided with permanent magnets arranged in a star-shaped manner, the permanent magnets are polarized in the direction of movement and the intermediate space between the individual permanent magnets in each case is filled by a ferromagnetic segment. Such an individual segment is generally produced as a laminated core and, therefore, may be denoted as a laminated core segment. The individual laminated core segments are, if possible, not connected together in order to avoid scatter.
The construction and production of an electric motor with magnets in flux concentration requires specific techniques: in particular, the construction should be scatter-resistant and suitable for mass production. Since a scatter-resistant construction generally requires the use of individual laminated segments, i.e. laminated core segments, and thus involves a higher production cost, such a construction hinders a mass production process. Previous embodiments of corresponding rotors were a compromise between individual rotor segment laminations, on the one hand, and rotor laminations, on the other hand, wherein the individual laminations are connected together. With complete rotor laminations it is achieved that the laminated rotor core is able to be produced in a more mechanically stable and simple manner but a portion of the flux of the magnets is short-circuited. This is made possible, for example, by stamped and stacked rotor cores in which the inner separating bridges are kept at defined spacings. Individual segments as are disclosed, for example, in the post-published European patent application EP 12 159 917.9 provide the advantage that a short circuit is not produced.
Moreover, in an individual-segment rotor with flux concentration the rotor lamination should be constructed so as to be separated by means of “non-magnetic” material (relative permeability μr<5) between each pole. This leads to a high number of individual segments which have to be joined together. Moreover, problems regarding the positioning and retention of the magnets and laminated core segments and the torque transmission have to be overcome.